Milling machine for copying or profiling



Dec. 12, 1939; H. F. ATKINS 2,183,344

MILLING MACHINE FOR COPYING 0R PROFILING 2 Sheets-Sheet 1 Filed Sept. 21, 1938 Han redenck ATKINJ 25 Inventor 24 23 22 by "8;. Atldrney Dec. 12, 11939.

H. F. ATKINS MILLING MACHINE FOR COPYING 0R PRQFILING 2 Sheets-Sheet 2 Filed Sept. 21, 1938 Inventor {5 Attorney Fredmnck \TK\ N5 mm nrm Fig. 3.

./4 I V //////V/////////// X.

Fzg 4 Patented Dec.12,1939 2 1 3 344 U I-Tostares- PATENT e ee MILLING MACHINE FOR COPYING on BROFILING v Harry' Frederick Atkins, OldFletton, Peterborough; England Application septemherzl, 1938, Serial No. 230,913 In;Great Britain August 11,- 1937 6 Claims. (01. 90-133) The inventionrelates to a milling machine able form is represented by the accompanying suitable for copying, profiling and like operations sheets of drawings.

of that kind in which a slide carrying the work Fig. 1 is .a front elevation of .the carrier-head and a pattern having exactly the shape and size and slide and other co-operative parts.

desired of the article to be manufactured is di- Fig. 2 is a.;horizontal section of Fig. 1. ametrically mounted upon, the face of a carrier- Fig. 3 is an. axial sectional elevation through head arranged for intermittent revolution at the the carrier-head, slide and stationary frame.- endof each traverse of the slide relative to. a Fig. 4 is afdetail section showing material parts milling cutter to operate on the work and in of the valve mechanism.

m -Which astylus or follower, which contactsthe Fig. 5 'isya detail sectionof such valve mechapattern, controls the movement of-the cutter., nism at right-angles to Fig. 4.

According to the invention a milling machine The revoluble carrier-head l is mounted by of the aforesaid kind. ischaracterised in that the roller bearings 2, 3, upon the stationary frame traverse of the slide is .efiected by hydraulic of the machine, parts of which are represented 15-means automatically controlled. through valve at G, to be revolved intermittently about the axis 15 mechanism by the intermittent rotation of the of the carrier-head by operation of a worm 5 carrier-head.. adapted to drive the worm-wheel periphery t of Further, according to the invention, said carsaid carrier-head, said worm being conveniently rier-head is held from revolving .by an automatic drivenby a friction drive, notshown. 2Q catch released by the completion of the traverse A slide 7 is diametrically arranged upon the ofthe slide, whereupon the carrier-head autoface of :thecarrier-head l, and also within said matically revolves, and the commencement of head at the back of the slide are arranged two this revolution automatically shuts off. the liquid. cylinders 8 and 9 having complementary doublepressure. 1 acting pistons l0 and II, said cylinders being 25.. According to constructional and functional parallelwith the slide and one on each side of I 25,

features of the invention, the hydraulic. means its. e e linea P 1 is p v ded w th a embodies either a single cylinder, with its. comoothed pinion 2 m n to v v up a plementary double-actingpiston, arranged with- 'diametric pin I l3 diSp0Sed intermediate e in the carrier-head parallel with the slide, or PiStOILendS, each Pinion gearing With pp 39.; two cylinders, and'their complementary doubleacks I4- and 15. carr ed, respectively, by the .30

acting pistons, one on each side of the centre of Slide and the ad, the Operation of the the slide andparallel therewith, the ends of .the Slide from t y i s and p stons being there,- cylinder or. cylindersbeing provided with ducts fore balanced- Thfipinion and rack gears are t form i l t, d h t" passages h i t such that the-slide is traversed in ratio of two are suitablyconnected to theslide, preferably by to one to the movement of the P18130118 3 and 35 a mechanism which multiplies the movement of At each of their ends e tWO cylinderscomthe slide in relation to the movement of the piston municate through ducts. l6 an w liquid or pistons, as for example by t t piniOn passage. I Scontrolled by valve action forboth mounted toirevolve u a-diametric m of inlet and exhaust by the intermittent revolution 4%piston and to engage two racks one upon the of the carrier-head, asiwill be hereinafter ole-'40 revoluble head and the other at the slide. The f these F 5 "passages will valve mechanism upon the inlet side of the liqbemately constlmtmg Inlet andexhauftuidgpressure is preferably provided with a Upon the carrier-head I, there ale provided pass valve which is normally open but closes autog lugs; 2a to co'operate w P "matically if any increased resistance is offered Ch 2 whlfih rmallyholds the carrieiehead .45

y, th th t t i from revolution, thic catch to be moved'out of to mac t 6 1 a greai er action by the completion of atraverse'of the pressure 15 temporanly unused overcome the slide '1. For this purpose,- the slide l is provided increasedresistance, said liquid pressurewith the with two pegs 25, oneof which, at vthe comple valve p being normally c l t tion of each traverse of the slide, pushes against normal machinme reslstance- The r an abutment 21 of the catch2l and forces said ui pp nd xh t rea se throush'the catch out of engagement withthe lug l9 or 2ev stationary frameof the machine to communicate. onthe carrier head. Wh t carrier. head i with the back of the revoluble carrier-head, hasthus been freed; itirevolvesv automatically a An embodiment of the inventionein its, desirhalf-revolutionhntilthe.other lug 19 is engaged, 55,

all)

by the catch. The slide 1 traverses always in the same direction after being turned round by the part-revolution of the carrier-head.

The driving gear for the worm 5 is in any sutiable way instantly started and stopped by the release and engagement of the catch 2| with one of the lugs l9 and 20.

The work 22 and a pattern 23, having exactly the shape and size desired of the article to be manufactured, are coincidently carried centrally,

upon the slide, and the milling cutter 24 and a stylus or follower 25 operate against said work and pattern, respectively. The cutter 24 and stylus 25 are usually carried on a common movable arm (not shown), arranged for lifting and lowering movements only to follow the contours of the pattern.

It will be readily understood that the work 22, illustrated as a cycle crank, is machined between its semi-circular ends during the traverse of the slide 1, and is machined around its semi-circular ends by the half revolution of the carrier-head l.

The construction and arrangement of the valve mechanism are illustrated in Figs. 4 and 5, the

position of the parts being with the carrier-head I held from revolution and the slide in course of traverse.

Pressure liquid, such as from an acciunulator, is supplied to the passage 28 provided within the stationary frame 4 to communicate by passages 29 and 30 with the passage l8 leading to the two ducts l5 and I! of the cylinders 8 and 9. The passage 30 and part of the passage 29 are in a spring pressed plunger 3| carried by the frame 4, and the passage I8 is in a spring pressed plunger 32 carried by the carrier-head l, and when these two plungers engage each other, as shown in Fig. 4, the passages 30 and I8 communicate, and the passages 29 are coincident, as also are passages 32a between the passage l8 and the ducts l6, [1,

so that pressure liquid enters the cylinders 8 and 9 to operate the pistons and traverse the slide.

It will be clear that the spring pressed plunger 3| is carried by the stationary frame 4, and that the spring pressed plunger 32 is carried by the revoluble carrier-head I, so that when the carrier-head automatically makes a part revolution the commencement of its movement instantly breaks connection between the passage 30 and I8, so that the spring pressed plungers 3| and 32 operate to close the passages 29 and 32a and therefore communication between the pressure liquid passage 28 and the cylinders, to thereby instantly stop traverse of the slide.

While liquid pressure is being supplied to the one ends of the cylinders the other ends of said cylinders are exhausting through one of the passages |8 to other suitable exhausting passages provided within the stationary frame 4. It follows from the aforesaid description that the hydraulic means is automatically controlled through suitable valve mechanism by the intermittent revolution of the carrier-head making and breaking the liquid joints between the passage 30 in the stationary frame and the passage [8 in the revoluble carrier-head.

It frequently happens in the milling of work, particularly when profiling, that resistance to the operation of the cutter temporarily increases, as for example, by a little harder metal being met with in the work. To provide for this contingency the pressure liquid supplied to the passage 28 is greater than normally needed for the work,

involving a by-pass valve 33 being provided in the stationary frame 4 to liberate the normal excessive pressure to an outlet 34 in said frame, this by-pass valve being normally spring pressed into open position, but adjusted to close onto its seating 35 only when the pressure at the passage 28 increases, i. e., greater resistance at the work, which will cause the valve 33 to automatically close and thereby increase the liquid pressure supplied into the cylinders 8 and 9 to overcome the temporarily increased work resistance which, on being removed, the by-pass valve 33 will again automatically reopen and the work proceed at normal liquid pressure.

The invention is applicable to a milling machine protected by my concurrent application Ser. No. 230,912 wherein the work and pattern are arranged to make swivelling or like movements additional to the movements of the slide and carrier-head.

Having now described my invention, what I claim and desire to secure by Letters Patent is:

1. In a milling machine of the kind described, the combination with a stationary frame, a revoluble carrier head, means to intermittently revolve said carrier head, a slide mounted transversely displaceable on said carrier head, and means to mount a pattern and the work on said slide, of hydraulic means to traverse said slide across said carrier head, and a valve mechanism to control said hydraulic means in dependence upon the intermittent revolutions of said carrier head.

2. A milling machine, as claimed in claim 1, in which said hydraulic means comprises a cylinder provided within the carrier-head parallel with the slide, a double acting piston slidable in said cylinder and connected with said slide, pressure liquid supply and exhaust ducts on said frame, ducts provided in the carrier-head at each end of the cylinder to form inlet and exhaust passages for pressure liquid, and valve mechanism provided between said ducts in the carrier head and said ducts on the stationary frame for automatically controlling the supply and discharge of pressure liquid to and from said cylinder in dependence upon intermittent revolution of the carrier head.

3. A milling machine, as claimed in claim 1, in which said hydraulic means comprises two cylinders provided within the carrier-head one on each side of the centre of the slide and both parallel therewith, two complementary double acting pistons slidable in said cylinders, respectively, and connected with said slide, pressure liquid supply and exhaust ducts on said frame, ducts provided in the carrier-head at each end of the cylinders to form inlet and exhaust passages for pressure liquid, and valve mechanism provided between said ducts in the carrier head and said ducts on the stationary frame for automatically controlling the supply and discharge of pressure liquid to and from said cylinders in dependence upon the intermittent revolution of the carrier head.

4. A milling machine as claimed in claim 1, in which said hydraulic means comprises a cylinder provided within the carrier-head parallel with the slide, a double-acting piston slidable in said cylinder, a toothed pinion mounted to revolve upon a diametric pin of said piston, racks on the carrier-head and slide, respectively, engaged by said pinion pressure liquid supply and exhaust ducts on said frame, ducts provided in the carrier-head at each end of the cylinders to form inlet and exhaust passages for pressure liquid, and valve mechanism provided between said ducts in the carrier head and said ducts on the stationary frame for automatically controlling the supply and discharge of pressure liquid to and. from said piston in dependence upon the intermittent revolution of the carrier head.

5. A milling machine, as claimed in claim 1, in which said valve mechanism includes a nor- 10 mally open by-pass valve adapted to close automatically as increased resistance is offered to machining,

6. A milling machine as claimed in claim 1, wherein said valve mechanism includes two spring pressed plungers co-operating with each other when the carrier head is at rest and one of them with a back circular face of the carrierhead during the intermittent revolution of said head.

HARRY FREDERICK ATKINS. 

